The prior art is rife with vibratory dispersion and counting devices of one kind or another, for separating pills into a single file, and then counting the tablets as they drop off the vibrating table. Once separated into a one-at-a-time profile, the pills are counted, and then placed in a vial.
The general principle in all of these devices is to shake the materials as they travel along a sloping path, in order to effect their separation. Despite the simplicity of the separation concept, these devices cannot be applied for applications requiring small apparatus, low complexity, light weight, low cost and minimal operator supervision. Problems arise when the shape and size of the pills vary. This variation most commonly requires unique parts for each table or capsule to accommodate the different shapes and/or sizes of the tablets. The need for a customized device, with changeable parts and/or extensive adjustments, unfortunately, defeats the purpose of providing a machine to perform pill counts automatically.
The present invention reflects the realization that any pill counting and dispersing system or machine must be reliable and accurate. The counting and dispensing system of this invention uses an innovative variation of the prior art vibratory tablet separating mechanism, with an improved actuating control system to help automate the procedure. The inventive system, with a single, three-position, mechanically adjusted metering device, is able to accommodate the complete range of different pill sizes and shapes.
In order to achieve the separation of the tablets, which is often called singulation, the inventive system does not use separate V-plates vibrating at different rates or amplitudes as shown in the prior art. Nor does this invention use long plates, often used in the prior art in order to allow the pills enough time to separate as they travel forward. Rather, this invention uses a single, relatively short, lightweight, concave-shaped, stepped trough, that is vibrationally driven electromagnetically at just a single point.
Despite the single vibratory control, this system is able to vibrate more strongly (with a larger amplitude) at its lower, dispensing end, than at its upper end. The difference in amplitude of vibration in the two ends of the trough provides an improved vibratory action, which for the first time accomplishes accurate singulation of tablets and capsules in such a small device.
The difference in amplitude of vibration is achieved by supporting the plate at each end with an elastomeric spring/damper support, the support at the upper end having a higher spring constant than the support at the lower end. This difference causes the lower end of the plate to vibrate with greater amplitude. The use of a single concave-shaped trough, driven at a single point and supported at only two points, achieves the simplicity, low cost, and compact form of the device.